A-4 Skyhawk

[KJ_Lesnick]

Would it have taken longer than the two-week period for an A-4 "whif" with a longer-nose like the A-4E, a cockpit with a normal seat-pitch (seat to rudder pedals - longer-canopy with the rear-canopy moved back a little bit further) to have been banged out?

Also,
-1.) What were the range requirements the USN wanted for the attack-plane design, and did Douglas barely make it or exceed it by a large margin?  Would the TA-4J have been able to make the range requirement?
-2.) Would a strake at the front of the wing have had any adverse effects on the area-ruling of the design or the overall handling characteristics of the plane?
-3.) How simple was the overall A-4 design?  Was there any advanced construction techniques used in it's development? 

KJ Lesnick

[jcf]

Would it have taken longer than the two-week period for an A-4 "whif" with a longer-nose like the A-4E, a cockpit with a normal seat-pitch (seat to rudder pedals - longer-canopy with the rear-canopy moved back a little bit further) to have been banged out?

Also,
-1.) What were the range requirements the USN wanted for the attack-plane design, and did Douglas barely make it or exceed it by a large margin?  Would the TA-4J have been able to make the range requirement?
-2.) Would a strake at the front of the wing have had any adverse effects on the area-ruling of the design or the overall handling characteristics of the plane?
-3.) How simple was the overall A-4 design?  Was there any advanced construction techniques used in it's development? 

KJ Lesnick

Kendra,
items such as precise nose length, cockpit arrangement etc., are not the kind of detail that would have been worked out in the proposal.
Proposals are just that; we propose to build you X with these general dimensions and target weights, powered by X engine and capable of the following target performance. Give us a contract and we'll do the design. A proposal is not a design and it is definitely not an actual aircraft.
An extremely simplified flow would be : Concept -> Proposal -> Design -> Product(Aircraft).

The requirements are in my earlier post:
top speed of 500mph, combat radius of 345 miles, 2,000lb weapon load and a maximum gross weight not to exceed 30,000lbs.
Douglas proposal: 600 mph, combat radius 460 miles, normal loaded weight less than 15,000 lbs, max gross weight @ 20,000lbs.

This page may be of help for actual production aircraft performance, including TA-4 specs:
http://www.skyhawk.org/2c/techdata.htm

The aircraft design was simple and strong, but that does not mean primitive, aerodynamically and structurally it was pretty much within the period state-of-the-art. The one-piece tip-to-tip spars were definitely an example early 50s high-tech machining.

Jon

[KJ_Lesnick]

joncarrfarrelly,

There are no range specs listed for any model to my knowledge on that particular page.  If you can find any information on the A-4C, and A-4E range wise, that would be useful. 

How much would the extra weight of an A-4E, A-4F, TA-4J type 'whiff' plane reduce range with a J-65 in it as opposed to a J-52 (since the first A-4's had J-65's)?  Would it still meet the 345 mile range hypothetically?

Kendra. 

[jcf]

Hi Kendra,
I've attached a scan of some A4D/A-4 specs.

Here is some engine data that may help in figuring out your concept:
J-65-W-20 (A-4C/A-4L): 1,268 kg (2,795 lb), 8,400lb thrust (earlier J65 were 7,700 and 7,800 lb thrust)

J-52-P-6A (A-4E,TA-4J):933 kg (2,056 lb), 8,500lb thrust

J-52-P-8A (A-4F/TA-4F, A-4G/TA-4G, A-4H/TA-4H ): weight; 961 kg (2,118 lb), 9,300lb thrust

Sources:
'Turbojet History and Development 1930-1960: Vol. 2", Anthony L. Kay, Crowood 2007
'Janes All the World's Aircraft: 1968-69"
'McDonnell Douglas Aircraft since 1920: Vol 1', Rene Francillon, Putnam/Naval Institute Press 1988

Cheers,
Jon or JCF... either is fine 

[KJ_Lesnick]

Jon,

The J-65 used on the earlier Skyhawks -- did it use a lower thrust due to the engine limitation, or because that was all the thrust they needed at the time? 


Kendra Lesnick

[jcf]

The lower thrust rating was the available output of the earlier series J65.
Based on the written sources the A4D-2N(A-4C) was originally produced with the lower powered W-16, but later received the more powerful W-20 when it became available. The A4D-2N(A-4C) was produced from 1959 to 1962.
According to Jane's most of the earlier Skyhawk fleet was progressively upgraded to the more powerful engine throughout the sixties.

Jon

[KJ_Lesnick]

Jon,

Could an A-4 "Whiff" with the longer nose, the longer cockpit and seat-pitch, with the extra weight that would go along with the modifications be able to get off the carriers that operated it, and achieve if not exceed the range requirements with even the early J-65's? 


K.J.
BTW: Also... the additional electronics that were fitted into the nose of the A-4E (I think) -- were the electronics added custom designed for the A-4?  Or was the size of the equipment already determined and the nose was simply lengthened around it? 

[jcf]

Jon,

Could an A-4 "Whiff" with the longer nose, the longer cockpit and seat-pitch, with the extra weight that would go along with the modifications be able to get off the carriers that operated it, and achieve if not exceed the range requirements with even the early J-65's? 


K.J.
BTW: Also... the additional electronics that were fitted into the nose of the A-4E (I think) -- were the electronics added custom designed for the A-4?  Or was the size of the equipment already determined and the nose was simply lengthened around it? 

The J-65 used more fuel than the J-52, the J-52 actually reduced consumption by 27% thus increasing range.
The longer nose and the minor mods to stretch the cockpit would add little weight to the basic structure.

The nose was first lengthened, by nine inches, on the A4D-2N(A4-C) to allow the installation of the AN/APG-53A terrain radar.
The later avionics additions required the development of the 'hump'.

Joe Baugher's site has a series of articles on the A4D:
http://home.att.net/~jbaugher4/newa4.html

Jon

[KJ_Lesnick]

Jon,

So the terrain following radar added, its size was pre-determined with the nose re-rigged around the extra equipment? 


BTW:  Was the nose-diameter (at it's thickest) roughly the same on all A-4 models?  I take it they moved the antenna forward on the longer-nosed versions (A-4C and afterwords)?   

Kendra

[dy031101]

Question: could escort carriers be able to launch and recover A-4 Skyhawks in air-to-air configuration (F model without the hump or Kahu mod. carrying AAMs and guns with or without droptanks)?

[ysi_maniac]

Recently read http://www.amazon.com/DOUGLAS-4-SKYHAWK-Close-Support-Fighter/dp/1844150852/ref=sr_1_14?ie=UTF8&s=books&qid=1215695874&sr=8-14

Wonderful stuff there. Just some notes:

A4D-4
-This project can be seen in Secret Projects forum-
Now in inception phase: thinking in matting an A-10 fuselage and A-7 wings

A-4D6
With TF-30 engine

Expanded span A-4
Twice wingspan. No extra fuel in wings but time on station 3.2 hours and radius of 740 nm (1370 km)

Submarine lanched
-In inception phase too-
Regulus and Regulus II were radio guided weapons. Prototypes of Regulus II were powered by J65 as
used in early A-4 and was intended to be carried operationally by the nuclear powered USS Halibut.
At some time in the 50s, Ed Heinemann made studies into adapting the A4D for carriage in the Halibut
huge hangar. Sketches were done that showed the SkyHawk could fit into the submarine hangar with
'minimum modification'. An all-new aircraft, the Douglas model 640 with flying boat hull was also
outlined by Heinemann.

Spey SkyHawk
This project can be seen in Secret Projects forum.

Spain was interested in A4 in competition with F-5
-Considering an A-4E or so with 3 colour spanish scheme-

A-4 for US Army, in my wish list too.

[KJ_Lesnick]

If anybody knows any of the answers to these, I'd appreciate it...

Since the design I was thinking of was to have a bigger cockpit (length-wise mostly though -- to make it easier to get in and out of the cockpit, to avoid such punishing ejections that the plane was known for, and the fact that it would later be used as a trainer), it was to have the longer nose of the A-4C for superior aerodynamics. 

What I'm wondering is is that even though the plane would have the longer nose, it would not feature the AN/APG-53A terrain-radar (and it probably wasn't even built yet), would the radar be placed in the same area of the airplane as it was on the first A-4's, or where it was on the A-4C's (If so, what would be placed between where the radar and the AN/APG-53A? -- a fuel tank?)? 

Would the WHIF have been as easy to reconfigure from the earlier A-4's to the versions *with* the AN/APG-53 (in otherwords, re-configure the plane to carry all that extra stuff in the allotted space)  Also, was the AN/APG-53 customized to the A-4, or modified to allow it to fit on the plane?


Kendra Lesnick,
BTW:  Since one of the ideas of my WHIF was that the TA-4 cockpit be along the same dimensions as the T-38 cockpit (which was far more reasonable in size for a trainer), could that fit into the design right (Or would it interfere in anyway with the hump being added later on?)

[KJ_Lesnick]

Another issue that I've just become aware of (within the past week or two) was the A-4's Thermal Cockpit Shield.  The cockpit shield took off an inch or two of head-room (I'm not sure if there was any further difference when deployed).  Did it take off any leg-room also (retracted and/or deployed)? 


Kendra Lesnick

[elmayerle]

One A-4 whif mod that appeals to me is tip-mounted Sidewinder rails, though you might have to reduce the sweep of the outboard leading edge to get an adequate chord length to mount the rails.

[GTX]

One A-4 whif mod that appeals to me is tip-mounted Sidewinder rails, though you might have to reduce the sweep of the outboard leading edge to get an adequate chord length to mount the rails.

That would look cool.

Regards,

Greg